Punch



- June 30, 1942. 4 c, F 2,287,882

PUNCH Filed April 25, 1941 5 *D- A 4 T155 1 L /9 E fi 7 I '2 v 9- IPatented June 30, 1942 2,287,882 PUNCH Lyman O. Huff, Chicago, Ill.,assignor to Universal Oil Products Company, Chicago, 111., a corporationof Delaware Application April 25, 1941, Serial No. 390,289

Claims. (01.164-124) The invention relates to an improved form of punchof a general type which comprises a holder and one or more removablepunching members or punch inserts, such as used, for example, in punchpresses, pilling machines and the like.

It is common practice in apparatus of the class above mentioned toretain the removable punching member or members in the holder by meansof a set screw or screws threaded into the'holder and bearing againstthe shank of the punch. Such an arrangement is particularly desirablesince it permits the replacement of broken or damaged punching memberswithout replacing the entire assembly or the holder. I have found,however, that when a punch breaks the break most frequently occurseitherat the face of the holder or at the approximate elevation of-theset screw. In either case it is extremely difllcult to remove the upperstub of the broken punch from the holder.

The invention obviates the disadvantage above "mentioned by providingthe removable punching member with a weakened section in its shank, saidsection being disposed at a point where the punching member may bebroken to the best advantage from the standpoint of facilitating itsremoval from the holder.

When, as is usually the case, the holder is provided with a set screwfor retaining the punch in place, the weakened section of the shank isdisposed outwardly or toward the face of the holder with reference tothe point at which the shank is contacted by the set screw. In suchinstances, I preferably provide a recess in the holder extending fromthe set screw port to the top of the well provided in the holder for thereception of the punch or, alternatively, I cut away a portion of theshank of the punching member from its inner endto a point thereoncorresponding to the elevation of the set screw.

With this last mentioned provision, pressure exerting means, such as agrease gun or the like, may be'secured to the holder at the set screwport, after the set screw is removed therefrom, to force cup grease oilor other suitable fluid into the punch recess and exert an outwardpressure on the broken stub of the punch to expel it from the holder.

Alternatively, the weakened section of the punching member may bedisposed at a point therein which is outside the holder when the punchis in place in the latter so that the break occurring at the weakened prtion will leave a grasped with pliers or the like to remove it there-Iv from.

The features and advantages of the invention will be more clearlyunderstood with reference to the accompanying diagrammatic drawing,comprising Figures 1 to 6 inclusive, which illustrates the invention inseveral of the specific forms which it embodies.

Figure 1 of the drawing is an elevational view of a punch andpunchholder with the latter shown in longitudinal section,

Figure 2 is a cross-sectional view of the punch and punch holder shownin Figure 1, this section being taken along line 2-2 in Figure l.

Figure 3 illustrates a portion of a modified form of punch embodying thefeatures of the invention.

Figure 4 is an elevationalview of another modified form of punch andpunch holder with the latter shown in longitudinal section.

Figure 5 is a cross-sectional view of the punch and punch holder shownin Figure 4, this section being taken along the line 55 in Figure 4.

Figure 6 is an elevational view of another .modified form of punch andpunch holder with the latter shown in longitudinal section.

, Referring to Figures 1 and 2, the punch holder 4 is designated by thereference numeral l and is provided with a relatively deep recess orwell for the reception of the removable punching member 2 and is alsoprovided with a threaded port 3 communicating with the punch recess anddis- 1 posed transversely thereto at a point between the inner end ofthe punch recess and the face of the holder from which the punchprotrudes. A set screw 4 is provided in port 3 to bear against the shankof the punch within the recess and retain it in place in the holder.

In the particular instance illustrated in Figure 1, the removablepunching member 2 is provided adjacent its upper end with a suitablenotched or flattened portion 5 against which the set screw 4 is adaptedto bear. A small segment is cut from the punching member, as indicatedat 6, ex'-. tending from the inner end of the punch to the portion 5thereof, to provide a continuous passageway from port 3 to the inner endof the punch recess when the punch is in place in the latter.

Anotch, indicated at l in Figure 1, is provided in the shank of punchingmember 2 at a point between section 5 thereof and the face of theholder. Notch lis of such form that the punch is weakened more at thispoint than at'section stub protruding from the holder which can be 5, sothat breakage of the punch will occur adjacent the notch I rather thanadjacent section 5. In the case here illustrated, the depth of thenotched portion at is substantially the same as the depth of the notchedportion I, as indicated by the dimension B in Figure 1, but therelatively flat bottom of notch 1, indicated by dimension A in Figure 1,is shorter than the relatively fiat section B at 5. Thus, stresses whichtend to break the punch are more concentrated adjacent section I thanadjacent section 5 and breakage will occur at the latter point.

To'remove the stub of a punch, such as illustrated in Figure 1 after ithas broken adjacent the notch I, the set screw 4 is removed and suitablepressure exerting means, such as, for ex-- ample, a grease gun, notillustrated, having a threaded fitting at its outlet end to screw intoport 3, is attached to the holder and cup grease or other suitable fluidis forced therefrom into the open portion of the punch recess formed bythe notched out portion at 5 and passageway 6. The pressure thus exertedagainst the bottom of the notched portion 5 will start the punch fromthe holder and admit fluid from passageway 6 between the top of thepunch and the end of the punch recess, forcing the broken stub from theholder.

In Figure 3, the modified form of removable punching member, hereillustrated, is designated by the reference numeral 8 and difiers frommember 2 of Figure 1 in that the weakened section of the punch at whichit is most likely to break is formed by a continuous groove 9 whichgives the shank of the punch a section C of smaller cross-sectional areathan the section D adjacent the segment removed from the upper end ofthe punch. In the case illustrated in Figure 3, the portion removed fromthe punch the holder that when a break occurs adjacent the groove, theprotruding stub may be grasped with a pair of pliers or the like toremove it from the holder.

ing members in a single holder) as well as to. sin-' gle punches such asillustrated.

The term punch or punching member" as used in the specification andappended claims "should not be interpreted as limiting the invenshank toprovide a bearing surface for the set screw is of continuous thicknessfrom adjacent its bottom to the upper end of the punching member andfunctions in much the same manner as the section 5 and fluid passageway6 in has no flattened or cut away portion for the set screw it in holderI 4 to bear against. However, there is still likelihood that the punchwill break adjacent the set screw and to avoid this a notch l5, similarto notch l in Figure l, is provided in the shank of the punch beneaththe point where the set screw bears against the shank. Inasmuch as thepunching member of Figure 4 has only one weakened section which isadjacent notch l5, it need not be weakened to such an extent as thepunches of Figures 1 and 3. Hence, the punch is proportionately strongerand will normally operate for a longer period of time without breakingIn the c'aseillustrated inFigure 4, instead of cutting away a portion ofthe shank of the punch adjacent its upper end to form a fiuid passagewayfrom the set-screw port Hi to the upper end tion to members which pierceor make indentations or openings .since the invention specificallycontemplates the adaptation of its. features to compressing and pillingmachinery or the like in which the punches act as compressing, pillingor ejecting members.

I claim as my invention:

1. A punch of the class described of substantially the same diameter atboth ends having a section of reduced cross-sectional area adapted to becontacted by a set screw for retaining the punch in a holder therefor,and having a second section of greater weakness than the first namedsection disposed intermediate the first named section and the outer endof the punch.

2. The punch defined in claim 1, wherein the second section is weakenedby a notch.

3. In apparatus of the class of punching, pilling and the like machines;the combination of a punch holder, a removable punch having a shankdisposed in a recess provided in said holder, the

holder having a port in its wall communicating with said recess andthreaded for the reception of a, set screw for the punch, the punchhaving a weakened portion disposed between the point where it iscontacted by the set-screw and the outer end of the punch, said weakenedportion being of less diameter than the diameter at said point and thediameter at said outer end.

4. In apparatus of the class of punching, pilling and the like machines,the combination ofa punch holder, a removable punch having a shankdisposed in a recess provided in said holder, the holder having a portin its wall communicating with said recess and threaded for thereception of a set-screw for the punch, the punch having a weakenedportion disposed between the point where it is contacted by theset-screw and the face of the holder, and means for establishingcommunication between the set-screw port and the innerend of the punchrecess.

5. In apparatus of the class of punching, pilling and the like machines,the combination of a punch holder, a removable punch having a shankdisposed in a recess provided in said holder, the

holder having a Port in its wall communicating with said recess andthreaded for the reception of a set screw for the punch, the punchhaving a weakened portion disposed between the point where it iscontacted by the set screw and the face of the holder, and the holderbeing provided with a fiuid passageway in its recess-defining wallextending from the inner end of the latter to and communicating with theset screw port.

6. In an apparatus of the class of pilling, punching and the likemachines, the'combination of a punch holder, a removable punch having ashank disposed in a recess provided in said holder, the holder having athreaded port in its wall communicating with said recess and threadedlyreceiving a set-screw [or the punch,.the'

punch having a weakened portion disposed between the point where it iscontacted by the setscrew and the face of the holder, that portion ofthe punch extendingv from its inner end to adjacent the set-screw portin the 'holder being constructed and arranged to provide a fluidpassageway from the set-screw port to the inner end of the punch recess.

'7. A punch of substantially uniform cross-sectional area having alongitudinally extendingportion of reduced cross-sectional areaextending from an intermediate point to one end thereof and anotherportion of reduced cross-sectional area disposed between the first namedportion and the opposite end of the punch, the second named portionbeing weaker than the first named portion, and being less incross-sectional area than said opposite end.

8. A punch of the class described, a segrnent of its shank being ofrelatively reduced cross-sectional area at and adjacent one end thereof,

said punch also being provided'with a recess therein at a point betweenthe aforementioned section of reduced cross-sectional area and" theopposite end of the punch, a section through the punch at said recessbeing weaker than any other section thereof, and being less incross-sectional area than said opposite end.

9. A punch of substantially uniform cross-sectional-area throughoutitslength, having a section of reduced cross-sectional area intermediateits ends in the form of a recess adapted to receive the end of aset-screw, said punch having another portion of reduced cross-sectionalarea extending from said recess to one endof the punch and having aportion of reduced crosssectionalarea disposed between said recess andthe opposite end of the punch, the punch being weaker at the lastdescribed portion than at any other portion thereof, and being less incrosssectional area than said opposite end,

10. A punch of the class described having a section of reducedcross-sectional area adapted to be contacted by a set screw forretaining the punch in a holder therefor, and having a second sectionweakened by an annular groove disposed intermediate the first-named,section andthe outer end of the punch.-

' LYMAN C. HUFF.

